Final answer:
Human chromosomes contain thousands of genes along with regulatory elements. Each gene can have multiple alleles, leading to trait variations. The genome also includes a significant amount of noncoding DNA with uncertain functions.
Step-by-step explanation:
Regarding the types of genes found on human chromosomes, each of the 23 pairs of chromosomes contains thousands of genes that contribute to a person's genotype and phenotype. In addition to the functional genes, there are also regulatory elements within the DNA that control the expression of these genes. Moreover, humans possess a mitochondrial genome, which is inherited exclusively from the mother and is separate from the chromosomal DNA.
Other kinds of genes you would expect to find on human chromosomes include those with alleles, which are different versions of the same gene. In the human genome, a single gene can have multiple alleles that contribute to variation in traits among individuals.
The genome also contains a large portion of noncoding DNA whose functions are not fully understood, but that may play roles in gene regulation and chromosome structure. Only about 25 percent of the DNA makes up genes and their regulatory elements, and of that 25 percent, only two percent actually code for proteins.